This application is not referenced in any Microfiche Appendix.
This invention relates to a method and an apparatus for fusing a plastic fitting to a plastic pipe. A typical means of attaching a thermoplastic component to a thermoplastic pipe is by heat fusion which means heating mating surfaces of a fitting and a portion of the exterior surface of a plastic pipe and while these surfaces are in molten states, joining the surface together under applied pressure and holding the pressure until the joined surface is cooled and are thereby fused to each other. Typically, the molten surfaces need to be held in juxtaposed positions for only a few seconds to cool to a solid state.
The basic concept of thermofusion of fittings to an exterior surface of a plastic pipe is well known. The method and apparatus herein are closely related to and constitute improvements on a sidewall applicator for heat fusion of a fitting to a plastic pipe as revealed in U.S. Pat. No. 5,505,811, which issued on Apr. 9, 1996. For further background information relating to methods and apparatus for fusing fittings to plastic pipe reference should be had to the following patents as well as to references cited in U.S. Pat. No. 5, 505 811.
This invention relates to an apparatus for fusing a plastic fitting to a plastic pipe.
The applicator of this invention includes spaced apart support shafts each having a lower end secured to the exterior of a plastic pipe so that the support shafts are in a common plane, normally a vertical plane, the plane including the axis of the plastic pipe. A housing is affixed on upper ends of the two support shafts. A vertical main shaft extends from the housing in the direction towards the pipe.
A transverse load cell is mechanically connected to the lower end of the main shaft and guided by the support shafts. A mechanically actuated brake is contained within the housing that releasable engages the main shaft, thus controlling the vertical position of the load cell.
The transverse load cell houses a hydraulically displaceable force shaft that telescopically extends downwardly from the load cell. A fitting holder is secured to the lower end of the force shaft. A hydraulic force generator in the load cell, operated by a hand wheel, provides hydraulic force to downwardly displace the force shaft so that a fitting, retained by the fitting holder, can be pressed against the exterior of the plastic pipe.